Now, they have added Barragan's teammate Negredo for the season in a bid to boost a strikeforce which already boasts Jordan Rhodes, Cristhian Stuani, and David Nugent.

The 30-year-old is best remembered by English supporters for his solitary season with Manchester City in 2013-14, when he scored 23 goals in all competitions largely in the first half of the campaign.

However, injury cut short that lethal form and he failed to score for the Premier League side after the third week of January.

He has struggled to recapture his previous form in two years at Valencia since that season, netting just 10 times for the La Liga side.

Regardless of his recent struggles, however, Negredo represents another hugely ambitious coup for Aitor Karanka's promoted Boro, and fans of other clubs on Twitter could scarcely hide their disbelief after the deal was announced.

Tom Nightingale

After starting to write about football due to lack of any great ability on the pitch, Tom is an NCTJ-qualified sports reporter who has written for Swansea City, the Birmingham Mail, and numerous other publications. An avid Aston Villa fan, he still hasn't got over them not turning up in the 2015 FA Cup final.